All of the member tribes have a historic relationship with the United States and European colonies through treaties, land reservations and other actions. But they have yet to gain official acknowledgment from the federal government.

"There have been increasing attacks against historic non-federally recognized tribes by some within Indian Country and increasing marginalization of historic non-federally recognized tribes by the federal government," John Norwood, ACET's General Secretary, said in an interview posted on the group's website.

ACET showed some of its prowess at the National Congress of American Indians 69th annual convention last month. The group's members successfully lobbied against a proposal to bar historic and state-recognized tribes from participating in NCAI.

"The problem is that too often members of federal tribes who overzealously seek to protect their culture from such overbearing non-historical enthusiast groups simply use the standard of federal recognition to do so, instead of using actual history," Norwood, who co-chairs NCAI's federal recognition task force, said in the interview. "They wind up grouping authentic tribes with the overbearing enthusiasts. This is undermining to all of Indian Country."

The group plans to push for the official acknowledgement of tribes from the eastern and southern seaboard.